Autoclaved Aerated Concrete: Difference Between Sand And Ash

Autoclaved aerated concrete is one of the most popular green building materials today, and the general public has highly appreciated it since it appeared on the market. Generally, Autoclaved aerated concrete is divided into autoclaved sand aerated concrete and autoclaved ash aerated concrete. However, do you know the difference between them? Today, let's find out!

What Is Sand Aerated Concrete?

Sand aerated concrete is a lightweight porous product made of silica material (sand or quartz tailings) and calcium material (lime, cement), mixed with aerating agent (aluminum powder), through the process of batching, mixing, pouring, pre-curing, cutting, autoclaving and maintenance.

What Is Ash Aerated Concrete?

Ash aerated concrete is a new type of wall material made of fly ash, lime, cement, conditioning agent, and aerating materials, through the process of batching, mixing, pouring, static stopping, cutting, and autoclaved maintenance. Its production process is basically the same as that of sand aerated.

Sand Aerated Concrete VS Ash Aerated Concrete

Features	Sand Aerated Concrete	Ash Aerated Concrete
Colour	Mostly off-white, or white with a little yellow	Mostly navy blue, or grey with a touch of green
Raw Material	The main raw material is finely ground sand	The main raw material is fly ash
Accuracy	In general, the appearance is flatter and the dimensional accuracy is slightly higher	has a flat appearance and high dimensional accuracy
Compressive Strength（under the same dry density condition）	The compressive strength of sand AAC is 3.5~7.5Mpa	The compressive strength of ash AAC is 2.5~5.0Mpa
Thermal Insulation (under the same compressive strength)	has a more complete and uniform pore structure than grey aerated, and the thermal insulation performance is better.	The pore structure of ash aerated is complete and uniform, with good heat insulation performance
Construction Method	Generally, dry construction is used, i.e. masonry with special binder	Mostly use wet construction method, that is, the use of mixed mortar masonry
Dry Shrinkage	The dry shrinkage ratio of sand aerated concrete blocks is smaller than that of ash, and the wall is less prone to cracking	Grey aerated concrete block walls are more prone to cracking
Energy Consumption	Sand needs to be mined and has a destructive effect on the environment where it is mined, and it consumes energy in mining and production, so the cost of producing sand aerated blocks is higher than the cost of ash aerated blocks.	Fly ash is the waste discharged from power plants, the production of fly ash aerated concrete blocks is waste utilization, and the cost is bound to be lower

Conclusion

Autoclaved sand aerated concrete has certain advantages compared with autoclaved ash aerated concrete. After all, sand aerated block is an updated alternative to traditional fly ash aerated block, and its advantages mainly lie in higher strength, and a greater improvement in seepage resistance, drying shrinkage, etc.

However, ash aerated concrete also has its own advantages, its raw material fly ash is the waste discharged from power plants, which is relatively lower cost, more economical, more energy-saving and environmentally friendly.